Downhole drilling, completion and production operations often utilize wellbore components or tools that, due to their function, are only required to have limited service lives and must be removed from or disposed of in the wellbore in order to recover the original size of the fluid pathway for use, including hydrocarbon production, CO2 sequestration, etc. Disposal of components or tools has conventionally been done by milling or drilling the component or tool out of the wellbore, which are generally time consuming and expensive operations.
The removal of components or tools by dissolution of degradable polylactic polymers using various wellbore fluids has been proposed. However, these polymers generally do not have the mechanical strength, fracture toughness and other mechanical properties necessary to perform the functions of wellbore components or tools over the operating temperature range of the wellbore, therefore, their application has been limited.
Other degradable materials have been proposed including certain degradable metal alloys formed from certain reactive metals in a major portion, such as aluminum, together with other alloy constituents in a minor portion, such as gallium, indium, bismuth, tin and mixtures and combinations thereof, and without excluding certain secondary alloying elements, such as zinc, copper, silver, cadmium, lead, and mixtures and combinations thereof. These materials may be formed by melting powders of the constituents and then solidifying the melt to form the alloy, or using powder metallurgy by pressing, compacting, sintering and the like a powder mixture of a reactive metal and other alloy constituent in the amounts mentioned. These materials include many combinations that utilize heavy metals, such as lead, cadmium, and the like that may not be suitable for release into the environment in conjunction with the degradation of the material. Also, their formation may involve various melting phenomena that result in alloy structures that are dictated by the phase equilibria and solidification characteristics of the respective alloy constituents, and that may not result in optimal or desirable alloy microstructures, mechanical properties or dissolution characteristics.
Therefore, the development of materials that can be used to form wellbore components and tools having the mechanical properties necessary to perform their intended function and then removed from the wellbore by controlled dissolution using wellbore fluids is very desirable.